FERNIE, B.C. - A three-year-old British Columbia boy who was smuggled over the U.S. border spent a cold and hungry night in a stolen vehicle with his father in the tiny Montana town of Whitefish, police say.

Robert Barnett, 39, was charged Friday with abduction and theft after a province-wide manhunt sparked by an Amber Alert that was eventually also triggered in Montana.

RCMP in Elk Valley, in southeastern B.C., issued the alert for Barnett's son, Alvin, after the pair disappeared Thursday following a supervised visit.

It was quickly learned the father had crossed the border into Montana in a stolen 2002 blue Subaru Outback.

The pair didn't make it far. Just 80 kilometres south of the border, Robert Barnett was seen by a man at the local bowling alley.

"He had offered him (Barnett) help," said Whitefish Police Lt. Bridger Kelch of the man who eventually called police.

"He just happened to be out,. He was approached by Barnett, he asked him for some assistance with possibility of some gas and food."

Kelch said the Whitefish resident told the man he could park his vehicle near his home, because it was better than sleeping in a well-lit parking lot.

"I don't know if he knew at that time that the kid was in the vehicle. He did not know that he was wanted at that time and then, when he woke in the morning, he observed the Amber Alert and thought it was pretty suspicious and that's when he contacted law enforcement."

Kelch said temperatures dipped down to about -7C in their area overnight.

Jennifer Viets, Montana's Amber Alert co-ordinator, said Thursday night that authorities were worried about the safety of the boy.

"We do consider it a dangerous situation."

But Undersheriff Dave Leib, of the Flathead County Sheriff's Office in Kalispell, Mont., said Friday that Alvin seemed untroubled by the event.

"The boy was wonderful," he said. "He was healthy and seemed very happy when he was here, wandering around our office."

"When he was returned, I received a call back from the Canadian Border Services and they said he was in very good shape."

Kelch said he knew little about Barnett's situation with the boy in Canada, other than that the father was supposed to be on a supervised visit with the boy and did not have custody.

Within hours of police moving in to arrest the father on Friday, the boy was returned to Canada.

"Thanks to the information that was broadcast by the Montana Department of Justice last night and an alert Whitefish resident, the suspect is in custody and the abducted child is now safe," Attorney General Steve Bullock said in a statement.

Robert Barnett has duel Canadian and U.S. citizenship. The man was born in Saskatoon, applied for American citizenship in Washington state while serving in the U.S. Army.

"At this time, he is not interested in going back to Canada," Leib said.

RCMP Cpl. Dan Moskaluk said expanding the Amber Alert into Montana was key to finding the boy in Whitefish.

Note to readers: This is a corrected story. A previous version incorrectly reported the undersheriff's name as Lieb.